There are three risk factors that tend to work synergistically to create a risk of repetitive stress injuries, Hatcher explains. Those risk factors -- posture, force and frequency -- create a triangle, similar in principle to the fire triangle of heat, fuel and oxygen.
That triangle provides a useful visual model for designing an ergonomics program.
"If you can knock out one of the legs of the triangle, you're well on your way to reducing the amount of risk," Hatcher says. He adds that many risk-elimination strategies are focused on improving posture.
When a safety professional considers the best approach to take in minimizing ergonomic risks, Hatcher says there's another visual model that's useful to conceptualize: a hierarchy of controls. This hierarchy of controls, in descending order, is comprised of:
- Engineering controls;
- Administrative controls; and
- Personal protective equipment.
The most effective way to minimize the risk of repetitive motion-related injuries is to "engineer out" the risks, according to Hatcher.
"If you're starting from scratch, and designing a machine or a job, you can design out 100 percent -- or close to it -- of the ergonomic risk," Hatcher said, adding that machines can be designed with proper horizontal reaches, grip diameters, work station heights and other ergonomic considerations in mind.
If engineering out the risk of repetitive stress-related injuries -- either through purchasing new equipment or retrofitting existing equipment -- isn't an option, a safety manager must consider administrative controls.
Administrative controls emphasize minimizing the machine operator's exposure to risk rather than trying to minimize the amount of risk present, according to Hatcher. Some administrative control tactics may include:
- Designing a job rotation schedule;
- Decreasing the frequency of certain movements by adding more operators to a particular job; or
- Changing job processes to lessen the amount of risk.
As it is a hierarchy, "the effectiveness of each of those controls gets a little bit less and less at each level," Hatcher said.
Opportunities for Improvements
In general, Hatcher says he commonly sees opportunities for ergonomic improvements in job tasks that involve:
- Loading and unloading from the floor;
- Extended reaches;
- Hand tools;
- Heights and reaches; and
As we established, the first and best option to consider is purchasing or designing ergonomically correct equipment (engineering controls). Equipment solutions for workplace ergonomic challenges can be found in Humantech's free, online database of vendors at http://www.humantech.com/Level2/publications_resourses/vendorweb.htm. (Humantech does not charge a fee to vendors for listing products on the site.) For example, type in "extended reaches" and the page brings up items ranging from a detachable keypad to a flexible workstation to a lift-and-tilt table, all of which are designed to minimize reaches and/or to keep work tasks in the operator's comfort zone.
And not all equipment solutions require the purchase of big-ticket items. Hatcher sees hand tools as a significant opportunity to reduce the risk of repetitive stress injuries.
"By switching from a regular wrench to some sort of battery-powered driver, you address all three sides of the triangle," Hatcher noted. "You cut out the frequency of having to twist the tool. You cut out awkward postures. And you cut out the force required. You engineer out a lot of the risk."
If your company budget allows for the purchase of ergonomically correct equipment, Hatcher cautions that it's not enough to order new machinery with the "ergonomic" tag on it, even if it is from a reputable manufacturer.
An important part of your due diligence must be ensuring that the equipment you're purchasing will be compatible with your existing machinery and processes.
"If you're not careful, blindingly buying equipment with the name 'ergonomic' attached to it can lead to increased costs down the road due to retrofitting," Hatcher said. Or the equipment might collect dust because it can't keep up with the pace of production in your plant.
Avoiding such pitfalls boils down to exercising the same kind of discretion you would when shopping for any other product. Most vendors, Hatcher says, can arrange for their customers to use their equipment on a trial basis. If that's not an option, Hatcher recommends making sure the vendor understands exactly what the job task you're purchasing the equipment for entails. It's also a good idea, if trials or prototypes aren't an option, to ask the vendor for pictures of the product in use by their current clients to get a sense of how it's used in the real world.
"If there's no task analysis or research and investigation or a throughout understanding of the job, you risk buying inappropriate equipment."
A Little Creativity Can Go a Long Way
If your company doesn't have hundreds of thousands of dollars earmarked for capital expenditures lying around, Hatcher says a bit of creativity can help the budget-conscious safety manager implement some engineering controls to improve workplace ergonomics.
"If you're a safety manager, make friends with the maintenance staff," Hatcher said. "Make friends with the guys with the portable welding equipment -- they can cut things off that can decrease reaches. Oftentimes people get creative with steel and a portable torch."
Another creative approach: Keep an eye out for existing equipment that, for one reason or another, is collecting dust somewhere in the plant. Through retrofitting or even a little jury-rigging, that equipment can become part of an ergonomics strategy. "Oftentimes there are conveyers and lift tables kicking around that nobody uses anymore. Either they took too much time or they broke down."
In Part 3 of our series on ergonomics, Hatcher presents a strategy that is critical to the success of your ergonomics program. Without it, your program might never get off the ground.